In the Spring of 1968, Herbert Simon gave a series of lectures at Massachusetts Institute of Technology, introducing his idea of a science of the artificial. “The world we live in today is much more a man-made, or artificial, world than it is a natural world,” he began to say, but modern science is a science of nature. “Natural science is knowledge about natural objects and phenomena. We ask whether there cannot also be “artificial” science–knowledge about artificial objects and phenomena.” He then set out to sketch a program for a general science of the artificial, defining it as a science of design: While the natural sciences are interested in how things are, the sciences of the artificial are concerned with how things might be–with design. The lectures were published in a book, The Sciences of the Artificial (MIT Press 1969), which became widely read, much admired and discussed. But readers were intrigued by the details, not by the general program. The idea of a science of the artificial simply never caught on. Simon made occasional attempts to revive it, but without the idea receiving any real attention. In 1993 we decided to try to correct this and launched a small project, sponsored by the Swedish Council for Planning and Coordination of Research, to advance the idea of a science of the artificial, beyond Simon’s original program. This book is a first contribution in this direction. In three essays, we discuss the idea of an artificial science, the more general issue of the nature of artifacts and our artificial world, and finally, the particular example of history as an artificial science. Some of these ideas were presented already in December 1994, at a seminar in Stockholm organized by the Council. We are grateful to the Council for its support and to the participants at the seminar for comments, criticism, and ideas.